
Considered the most demanding among the classic routes of this mountain range, the trail requires considerable effort. In summer, high temperatures and sun exposure make the crossing more challenging, which is why many prefer to start at sunset and finish at night. In winter, it's only suitable for mountaineers due to accumulated ice and snow across the terrain.
It's crucial and equally advisable to attempt this route only in optimal weather conditions. Without adequate wind protection, completing the route becomes impractical, especially considering potential fog conditions.

The name Cuerda Larga (Long Ridge) comes from the practically horizontal line formed by the eight summits along this route. The peaks comprising it are: Bola del Mundo, Cerro de Valdemartín, Cabeza de Hierro Menor (Minor Iron Head), Cabeza de Hierro Mayor (Major Iron Head), Loma de Pandasco, Asómate de Hoyos, Los Bailanderos, and La Najarra.

As a linear route, the start and end points are naturally different, allowing you to begin from either end. Unless travelling with an organised group that provides transport between endpoints, you'll need to arrange vehicles at both locations.

Technical Details:
- Difficulty: High
- Start and finish: Puerto de Navacerrada or Puerto de la Morcuera
- Duration: Approximately 5 hours
- Distance: 20 km
- Elevation gain: 600 m
The trail follows well-marked paths, and orientation is straightforward unless fog occurs. To the north lies the Lozoya Valley and to the south the Santillana Reservoir. Essential equipment includes: a backpack, water bottle for hydration, cereal bars or nuts... (Check out basic hiking equipment). When walking above 2000 metres, include a fleece, gloves and hat.

How to get there
-By car:
- From Madrid take the A-6 towards A Coruña until exit 39 for Puerto de Navacerrada via the M-601.
- From Segovia take the CL-601 and continue on the M-601 to Puerto de Navacerrada.
- Bus: Take line 691 from Moncloa.
- Train - Cercanías: Line C9.